A new seismic daylight imaging method for determining the structure of lithospheric discontinuity
A new seismic daylight imaging method for determining the structure of lithospheric discontinuity
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确定岩石圈不连续结构的地震日光成像新方法
DOI：
10.1007/s11430-018-9249-3
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发表时间：
2018-10
期刊：
影响因子：
--
通讯作者：
Tang Qingya
中科院分区：
文献类型：
--
作者：
Sun Weijia;Fu Liyun;Wei Wei;Tang Qingya
岩石圈不连续面的精细结构包含有关岩石圈形成、发展、转化和破坏动力学的重要信息。本文发展了一种新的地震日光成像方法，用于探测岩石圈不连续的小尺度结构。该方法利用远震事件在0.5-4赫兹高频段的P波初至和尾波，对岩石圈不连续面的分辨率达到2公里。这种方法的基本原理是，地震台下垂直入射传输响应的自相关等价于震源和台站在自由面上的反射响应。传播响应包括在台下穿过不连续面到达自由面的初至P波，以及自由面和不连续面之间的多次反射。在本研究中，将该方法的垂直入射要求进一步扩展到包括倾角入射照明，从而扩展了该方法的适用性。用合成的理论地震图验证了地震日光成像理论的准确性和可行性，并讨论了影响成像结果的因素。给出了该方法的资料处理步骤和解释判据。用该方法确定了中国克拉通东部两个永久台站的精细岩石圈结构和瞬时频率。在这两个台站下方52公里和75公里处的岩石圈地幔中发现了明显的不连续。地震白天成像和接收函数揭示了西澳大利亚克拉通MBWA永久站下方更一致的岩石圈结构，并明确存在岩石圈不连续。高频SDI可以用来探测岩石圈的精细结构。由于它的波形比较复杂，因此建议适当参考现有的地震信息，如层析速度反演和接收函数。
The fine-scale structures of lithosphere discontinuities contain important information on the dynamics of lithosphere formation, development, transformation, and destruction. In this paper, a new seismic daylight imaging method is developed to explore the small-scale structures of lithosphere discontinuities. This method makes use of the P-wave first arrival and coda in the 0.5–4 Hz high frequency band of teleseismic events, and reaches a resolution of 2 km for lithosphere discontinuities. This method rests on the basic principle that the autocorrelation of the vertically incident transmission response below the seismic station is equivalent to the reflection response with the source and station both on the free surface. The transmission responses include the first-arrival P-waves below the station traversing the discontinuities to reach the free surface, and the multiple reflections between the free surface and the discontinuities. In this study, the normal incidence requirement of the method is further extended to include dip incidence illumination, which expands its applicability. The accuracy and feasibility of the seismic daylight imaging (SDI) theory are verified by synthesized theoretical seismograms, and the factors affecting the imaging results are discussed. The data processing steps and the interpretation criteria for the method are also given. The fine-scale lithosphere structure of two permanent stations at the eastern North China Craton is determined by the method described here, as well as instantaneous frequency. Clear discontinuities are found in the lithospheric mantle at 52 and 75 km below the two stations, respectively. Seismic daylight imaging and the receiver function reveal a more consistent lithosphere structure beneath the MBWA permanent station of the West Australia Craton, with the unmistakable presence of the lithosphere discontinuities. High-frequency SDI can be used to detect the fine-scale lithospheric structures. As its waveform is more complex, and hence appropriate reference to existing seismological information, such as from tomographic velocity inversion and the receiver function, is recommended.
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影响因子：
2.9
作者：
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通讯作者：
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影响因子：
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DOI：
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期刊：
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影响因子：
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DOI：
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发表时间：
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期刊：
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影响因子：
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